Radiation may replace axillary lymph node dissection after SLNB-detected N1 disease

SAN FRANCISCO — Radiation and axillary lymph node dissection conferred similar OS and RFS among patients with pathological N1 breast cancer detected by sentinel lymph node biopsy after mastectomy, according to study results presented at the Breast Cancer Symposium.

However, radiation was associated with less toxicity, results showed.

Recent research suggested that axillary lymph node dissection (ALND) was unnecessary after lumpectomy in patients with one to two positive nodes detected by sentinel lymph node biopsy (SLNB), according to background information provided by researchers.

In the current study, Yun Fu, MD, of the department of breast surgery at Shanghai First Maternity and Infant Hospital, and colleagues sought to evaluate the role of ALND after mastectomy.

The analysis included 214 patients with primary invasive breast cancer who underwent mastectomy at the University of California, Los Angeles, between 2002 and 2010.

All patients underwent lymph node staging surgery. Those who underwent SLNB as their first nodal surgery then underwent observation, radiation, or additional ALND with or without radiation. Patients who underwent ALND as their first nodal surgery did so with or without radiation.

Median follow-up was 43.6 months.

Among patients who underwent SLNB, 5-year OS rates were 71% among those who underwent observation, 94% among those who underwent additional ALND and 100% among those who received radiation (P=.031).

Researchers reported recurrence among 17.4% of patients who underwent observation, 7.8% of those who underwent additional ALND and 0% among patients who underwent radiation (P=.046).

Patients who underwent ALND as their first surgery were more likely to experience pain (P=.021) and lymphedema (P=.043) than those who underwent SLNB as their first surgery.

Results of a multivariate analysis controlled for type of nodal surgery and radiation found systemic recurrence was significantly associated with younger age (HR=0.92; 95% CI, 0.85-.98), higher histological grade (HR=5.57; 95% CI, 1.29-23.95) and positive HER-2 status (HR=8.91; 95% CI, 1.59-49.99).

HER-2 status also was significantly associated with OS (HR=7.49; 95% CI, 1.78-31.52).

“Radiation was as effective as complete axillary lymph node dissection in patients with mastectomy and N1 disease detected by SLNB for OS and RFS rates, yet radiation after SLNB had fewer side effects than axillary lymph node dissection,” Fu and colleagues wrote. “SLNB followed by radiation could replace axillary lymph node dissection in patients with mastectomy and pathological N1 breast cancer identified by SLNB.”

For more information:

Fu Y. Abstract #101. Presented at: Breast Cancer Symposium; Sept. 4-6, 2014; San Francisco.

Disclosures: The researchers report consultant/advisory roles with, research funding from and stock ownership in Bristol-Myers Squibb, Genomic Health, Johnson & Johnson, Merck, Pfizer, TERA and Xoft.